Steel guitar tuning mechanism



July 1, 1969 I s s ET AL 3,452,635

STEEL GUITAR TUNING MECHANISM Filed Jan. 4, 1967 Sheet of s w 16V 17 15 14 flee/L I I I; 7. .7 .7 91 M j INVENTORS 4L 4 628526, BY 304/440 67 624/71/ y ,,1969 R. A. SEBERS ET AL 3,452,635

STEEL GUITAR TUNING MECHANISM.

Filed Jan. 4, 1967 Sheet '2 0f 3 INVENTORS' b Bum/4. $3595, By 00mm 5 6914/76 ,1969 R. A. SEBERS ET AL STEEL GUITAR TUNING MECHANISM Sheet Filed Jan. 4, 1967 W mg w W 4 W Z 4 m 4 1 6w l m f. MIN MQ Wa m mmw v wkfiml \whN g United States Patent 3,452,635 STEEL GUITAR TUNING MECHANISM Ralph A. Sebers, 2303 12th Ave., and Donald E. Smith, Rte. 3, both of Rochester, Minn. 55901 Filed Jan. 4, 1967, Ser. No. 611,528 Int. Cl. G10d 3/14 US. Cl. 84-312 23 Claims ABSTRACT OF THE DISCLOSURE The disclosure of this application is directed to a mechanism for changing the pitch of a stringed instrument while it is being played by changing the tension on the strings through the use of controlled linkages forming one of the bridges. Through the use of foot or knee pedals, a change of key may be made without resort to touching the tuning head. A string tightening mechanism is provided permitting a quick replacement of a broken string.

The tuning mechanism includes means for increasing and decreasing the tension on a plurality of strings where the tension on certain of the same strings has varied previously and remained in such condition.

Prior art workers have recognized that it is desirable to be able to change the pitch of a string on a lute-type instrument such as a steel guitar by the manipulation of a lever which is usually foot operated. However, the mechanisms for accomplishing this desired operation are generally complicated and are generally designed so that they may increase or decrease the pitch of a string, but not both while one is taking place. That is, it is most desirable in the playing of an instrument such as a steel guitar, to be able to change the tension of the strings so as to increase or decrease the pitch by the use of a lever and while the lever is still held in place, change the tension on the string a second time which has the opposite effect as that first incurred. The attempts to adjust the tension on the strings has generally been confined to those types of devices in which the so-called neutral position of the tension on the string is balanced through the use of several springs. It will be recognized that as the springs are flexed, the neutral point tends to shift and thus the instrument must be retuned to achieve the neutral position. Thus an instrument in which the tension of the strings may be increased as well as decreased while already under a tension changing operation provides great versatility for the performer playing the instrument. Furthermore, it has been found that very little improvement has been made to the string tuning mechanism of the instrument and where a string must be replaced, a tedious task is encountered in making several turns of the string around a binding post before being secured at the proper pitch or tension of the string. The present invention provides an easy and uncomplicated means of securing the string to the tuning mechanism.

It is therefore a general object of the present invention to provide an improved tuning mechanism for a lute-type instrument such as an electric steel guitar.

It is another object of this invention to provide a means for increasing and decreasing the tension of a guitar string through the same relative movement of two different control arms.

It is a further object of this invention to provide means for limiting the increase or decrease in the tension on any string.

It is a further object of this invention to provide a tuning mechanism having means for increasing and decreasing the tension on a plurality of strings where the tension on certain of the same strings has varied previously and remains in such condition.

3,452,635 Patented July I, 1969 It is still another object of this invention to provide a tuning mechanism having lost motion devices to change the tension on the strings.

It is still another object of the present invention to provide an improved tuning mechanism having a coarse control device for setting the initial tension on the strings.

These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which:

FIG. 1 is a perspective view of an electric steel guitar incorporating the invention;

FIG. 2 is a diagrammatic view of the invention showing the structure as used on each string;

FIG. 3 is a perspective View of a string tuning mechanism used with the invention;

FIG. 4 is a plan view of a guitar as seen from the bottom showing the operating mechanism;

FIG. 5 shows a perspective view of the string tuning mechanism used in the invention;

FIG. 6 is a diagrammatic view of the invention showing a modified structure as used on each string;

FIG. 7 is a detailed elevation view in partial section of the linkage arm connected to one of the transverse shafts;

and

FIG. 8 is a detailed elevation view in partial section of a knee operated lever connected to one of the transverse shafts.

In FIG. 1, a steel guitar 10 having a body portion 11 is box-like in shape with an opening facing downwardly. A magnetic pick-up 14 is secured to body portion 11 under ten strings 15a through 15f, the magnetic pick-up 14 forming no part of the invention. Secured to the end of neck 12, is a string tuning mechanism referred to generally as numeral 16, and a bridge 17. Secured to each of four corners of frame 13, are four adjustable telescopic legs through 23. Secured to legs 21 and 22 (which are the legs pointing to the front of the instrument) is a cross-bar 24. Six foot pedals 25 through are pivotally secured to cross-bar 24 and operate six vertically operated control rods through respectively.

Reference is now made to FIG. 2 wherein the controlling mechanism is shown which is associated with string 150, it being understood that a like mechanism is associated with each of the strings connected thereto. String 15a is anchored over a cam 41 (also see FIG. 3) which is secured to the string tuning frame 16 by a rotatable member having a worm gear wheel 42 connected thereto.

String 15a extends over bridge 17 at one end of the guitar and over another bridge tail piece 43 in the form of a link which supports the string, and secures it in a locking bore 44. In other words, the string passes over the upward portion of the link into an anchoring bore 44. A groove 45 is formed across the top of the link which is somewhat rectangular in nature with a curved portion at the top to provide a good bearing surface for string 15a. Link 43 has a notched portion 46 fromed in the front or leading edge of link 43 near its upper end where string 15a passes thereover. A knife edge bracket 47 which is secured to frame 13 engages notch 46 to provide a fulcrum for lever 43. Thus it will be seen that by moving link 43, either clockwise or counterclockwise, the tension in string 15a will be increased or decreased respectively. The lower portion of link 43 is in the form of an inverted U-shaped member through which a bore 48 is formed transverse to the legs of the member. Another link 50 is connected to link 43 by a pin 51 passing through bores 48 and another hole formed in link 50 (not shown). Link '50 has a hole formed near the bottom thereof and an arm 53 is pivotally secured in hole 52 and extends towards the string tuning mechanism where it passes through a hole 54 formed in a guide member 55. Guide member 55 is in the form of an arm extending downwardly from frame member 13. The end portion of rod 53 has threads 56 formed thereon and a stop collar 57 is secured to rod 56 in such a manner as to restrict the movement of arm 53. Another hole 60 is formed in link 50 below hole 52 and has a spring 61 connected thereto which is under tension and secured to frame 13. That is, spring 61 exerts a force in the direction opposite that of the direction in which arm 53 is extended. A notch 62 is formed on the side of link 50 which contains spring 61 at a point approximately to /3 the distance from pin 51 towards hole 52. Another arm 63, having a looped portion 63a engaging notch 62, extends under the neck portion 12 and passes through a hole 64 formed in guide 55. Rod 63 also has a threaded portion 66 formed on the end thereof and a collar 67 secures rod 63 against movement.

It will now be seen that links 43 and 50 are in a state of equilibrium and that string 15a may be properly set for the right pitch. Since spring 51 exerts a force against link 50, upon movement of rod 63 away from link 50, it will be seen that link 50 pivots about arm 53 at hole 52 and that link 43 pivots clockwise about fulcrum 46 so that the tension on string 15a is increased. On the other hand, with rod 63 at rest, movement of rod 53 away from link 50 causes link 50 to pivot about loop 63a in notch 62 and thus through the use of pin 51, pivot link 43 counterclockwise to decrease the tension in string 15a. By the use of a pair of second stop collars 58 and 68 secured to screw threads 66 and 56 respectively, control may be had over the magnitude of the change in tension on string 15a. Thus collar 68 may be set to limit the increase in string tension and collar 58 may be used to limit the decrease in string tension.

Rod 63 has six depending loops formed therein extending between loop 63a and threads 64, loops 70 and 71 being shown. It will be understood of course that four additional loops are formed in rod 63 and as will be clearly shown, will operate with control rods 35 through 40. In addition thereto, arm 53 has six depending loops formed as a part thereof which extend between hole 52 and threads 56, loops 72 and 73 being formed directly below loops 70 and 71 of rod 63.

A pair of shafts 74 and 75 are rotatably secured to frame 13 and are located directly above loops 70 and 71 respectively. A pair of lever arms 76 and 77 are secured to shafts 74 and 75 respectively and have a pair of holes 78 and 79 formed in the opposite ends thereof which are connected to control rods 35 and 36 respectively. It will of course be understood that four additional shafts are secured transverse to the guitar frame 13, each having a lever arm secured thereto to be connected to the appropriate foot pedal through the appropriate control rod. A pair of levers 80 and 81 are secured to shafts 74 and 75 respectively and depend downwardly to cooperate with loops 70 and 72, and loops 71 and 73 respectively. A pair of screw holes are formed in lever 80, with a screw hole 82 cooperating with loop 72 and a screw 83 being secured in the screw hole cooperating with loop 70 so that the head of screw 83 slidably engages loop 70 at the end nearest the guide arm 55. In a reverse manner, a screw hole 85 is formed in lever 81 to cooperate with loop 71 and a screw 86 is secured in a hole which cooperates with loop 73 so that loop 73 is slidably engaged with screw 86.

Thus it will be seen that when pedal 25 is depressed, control rod 35 is moved downwardly causing arm 80 to rotate clockwise and since screw 83 engages loop 70,

.control rod 63 is moved towards guide arm 55 increasing the tension in string 15a. In a similar manner, depressing pedal 26 causes control rod 36 to be moved downwardly and rotate lever 81 clockwise, thus moving arm 53 to- 4 wards guide arm 55 to produce a decrease in the tension on string 15a. It should be noted that loops 70 through 73 and the cooperating screws form a lost motion device so that when a pedal is depressed, if another pedal is depressed afterwards while the first is being held in its downward position, with screws 83 and 86 both located to control the same arm (53 or 63), no additional movement will be produced in link 43 and the tension on string 15a will remain the same. It will also be recognized that by connecting the arms of the other strings to pedals controlled by shafts 74 and 75, the pitch of several strings may be changed and thus a change of key may be made by the musician. It should also be recognized that the slots formed by the loops in arms 53 and 63 may be formed instead in levers and 81 with the screws held by the arms to engage the slots at the ends opposite to that just described.

Stop collars 68 and 58 may be set to limit the increase or decrease in string tension and thus limit the range of the variation that may take place. Stop collars 68 and 58 may be set to provide the maximum travel of arms 53 and 63 and pedals 25 through 30 may have a stop associated therewith which will allow increments of the full travel of arms 53 and 63 thus allowing one pedal to flat or sharp a note and another pedal to add an additional change of pitch by one-half step or more.

It will also be recognized that the force required to depress pedals 25 through 30 will vary, according to the number of arms which are to be actuated. For instance, one pedal may move only two control rods while another pedal may move four. Thus the force required to depress the pedal will be approximately twice that for the pedal having only half as many control arms. Under such conditions, it may be advisable to provide an adjustable lever arm such as lever arms 76 and 77 by placing the control rods in the eye of an adjustable screw which will be moved radially towards, or away from, the rotating shafts such as shafts 74 and 75.

FIG. 5 shows the string tightening arrangement wherein frame 16 carries ten keys 91 through which have a worm screw formed as a part thereof in the conventional manner. The worm screw engages the worm wheel such as worm wheel 42 (FIGS. 2 and 3), the worm wheel 42 being rotatably secured to frame 16 and having cam 41 formed on the end thereof. It will of course be recognized that the other strings are connected to a similar mechanism. Cam 41 has a groove 102 formed in the upper portion thereof which is formed to receive the string such as string 15a and coincides with a bore 103 formed transverse to the slot or groove 102 below worm wheel 42 and forward thereof. Bore 103 receives a slidable stud member 104 which has a finger engaging knob 105 formed at the end thereof. A hole is drilled transversely through stud 104 and is adapted to receive a pin 106 which lies in grooveor slot 102 and restricts rotational movement of stud 104. Another hole 107 is formed above pin 106 in stud 104 and is adapted to receive the string such as string 15a. In using the mechanism, cam '41 is rotated to a position where stud 104 projects upwardly and the string is passed through the hole 107. Stud 104 is pulled upwardly to disengage pin 106 from groove 102 and is then rotated until the string is tightened by manipulation of knob 105 and is then pressed downwardly so that pin 106 again engages groove 102. Key 91 is then rotated until the string is tightened to its proper pitch.

Reference is now made to FIG. 6 wherein the controlling mechanism is shown associated with string 15a, it being understood that a like mechanism is associated with each of the strings connected thereto. String 15a is anchored over a cam 141 which is secured to neck 12 through a support member 116 and a stationary member such as a shaft 142.

String 15a extends over another bridge tail piece 143 in the form of a link which supports the string, and secures it in a locking notch 144. In other words, the string passes over the upward portion of the link into an anchoring notch or groove 44. A groove 145 is formed across the top of the link with a curved portion at the top to provide a good bearing surface for a string. Link 143 has a notched portion 146 formed in the front or leading edge of link 143 near its upper end where string a passes thereover. A knife edge bracket 147 which is secured to frame 13 engages notch 146 to provide a fulcrum for lever 143. Thus it will be seen that by moving link 143, either clockwise or counterclockwise, the tension in string 15a 'will be increased or decreased respectively. The lower portion of the link 143 has a bore (not shown) formed transverse to the member. Another link 150 in the form of a U-shaped member is connected to link 143 by a pin 151 passing through the bore just described and another hole 148 formed in link 150. Link 150 has a hole 152 formed near the bottom thereof and an arm 153 is pivotally secured in hole 152 through the use of a lug 153a formed therewith. Arm 153 extends towards the string tuning mechanism where it passes through a hole 154 formed in a guide member 155. Guide member 155 is in the form of a bracket connected to the downwardlyextending portion of frame member 1 3. The end portion of rod 153 has threads 156 formed thereon and a stop collar 157 is secured to rod 156 in such a manner as to restrict the movement of rod 153 to the right as seen in FIG. 6. Another hole 160 is formed in lug 153a, the hole being below hole 152, and has a spring 161 connected thereto which is under tension and secured to frame 13. That is, spring 161 exerts a force in the direction opposite to that of the direction in which arm 153 is extended. Another hole 162 is formed in both sides of U-shaped link 150 at a point approximately A1 to /3 the distance from pin 151 towards hole 152. Another arm 163 has a lug portion 163a lying between the two legs of link 150 and secured thereto through hole 162 by a pin 162a. Rod 163 extends under the neck portion 12 and passes through a hole 164 formed in guide 155. Rod 163 also has a threaded portion 166 formed on the end thereof and a collar 167 secures rod 163 against movement in a manner described previously relating to rod 153. A spring 59 is connected to lug 163a through a hole 159. Hole 159 is located vertically between pins 151 and 162a and the spring generally exerts less force than that of spring 161 and in a direction opposite to that of spring 161.

It will now be seen that links 143 and 150 are in a state of equilibrium and that string 15a may be set for the correct pitch. Since spring 161 exerts a force against link 150, upon movement of rod 163 away from link 150, it will be seen that link 150 pivots about arm 153 at hole 152 and is aided by spring 59, thus causing link 143 to pivot clockwise about fulcrum 146 so that the tension on string 15a is increased. On the other hand, with rod 163 at rest, movement of rod 153 away from link 150 causes link 150 to pivot about pin 162a and thus through the use of pin 15 1, link 143 is rotated counterclockwise to decrease the tension in string 15a. By the use of a pair of second stop collars 158 and 168 having threads 168a and 158a respectively on rods 163 and 153, control may be obtained over the magnitude of the change in tension on string 15a. The stop collars work against a guide member 155a which is secured to the end of the body frame 13. A provision is made in the side of frame member 13 for adjusting collars 168 and 158 by the musician. In other 'words, collar 168 may be set to limit the increase in string tension and collar 158 may be used to limit the decrease in string tension.

A pair of shafts 174 and 175 are rotatably secured to frame 13 and are located directly above rod 163 and 153. A pair of adjustable lever arms 176 and 177 are secured to shafts 174 and 175 respectively and have a pair of holes 178 and 179 formed in the opposite ends therecontrol rods 135 and 136 respectively. As described previously, four additional shafts are secured transverse to the guitar frame 13, each having a lever secured thereto to be connected to the appropriate foot pedal through the appropriate control rod. A pair of downwardly extending levers 180 and 18 1 are secured to shafts 174 and 175 respectively by a pair of screws 180a and 181a. A pair of grooves 170 and 172 are formed in the edge of lever 180 to cooperate respectively with rods 163 and 153. In other words, the grooves are of sufiicient width to allow the rods to move freely in the space provided therein. In like manner, another pair of grooves 171 and 173 are provided in lever 181 to also accommodate rods 163 and 153 respectively in the same manner as just described. A pair of sleeves 183 and 186 are fitted over rods 163 and 153 respectively and are adapted to engage levers 180 and 181 respectively. They are secured in place by a pair of set screws 183a and 186a. If the rods are not to be controlled by a particular lever, then sleeves 183 and 186 should be moved to the left (as seen in FIG. 6) and thus they will not engage the particular levers.

It may also be desirable to widen lever 180- and have another pair of grooves similar to grooves 170 and 171 on the opposite side of lever 180 to engage the sleeves on the arms of the adjacent mechanism for the adjacent string. Of course the same variation may be made to all the other levers such as lever 181.

It will therefore be seen that when control rod or cable 135 is drawn downwardly, causing arm 180 to rotate clockwise, control rod 163 is moved towards guide arm 155 thus increasing the tension in string 1511. In a similar manner, depressing another pedal to which is attached cable or control rod 136, rotates lever 18 1 clockwise, thus moving arm 153 towards guide arm 155 to produce a decrease in the tension on string 15a. It should be noted that if another sleeve is located adjacent another lever on the same control arm, it will form a lost motion device so that when a pedal is depressed, if another pedal is depressed afterward while the [first is being held in its downward position, with sleeves 183 and 186 both located to control the same arm (153 or 163), no additional movement will be produced in link 143 and the tension on string 15a will remain the same.

In FIG. 8, there is shown a variation of the foot operated pedal by using a knee lever 125. Secured across the body frame on the side adjacent the player, is a horizontal rod which is secured to frame 13 by the use of a fastening device such as screws 111. A collar 112 has a bore formed therein and is adapted to slide along rod 110 and be secured thereto below the transverse shafts by suitable means such as screws 111. A slot 113 is formed in collar 112 parallel to arm 176 and the upper end of knee lever 125 is secured in the slot by the use of suitable means such as a pin 114. Knee lever 125 has an extendible lug portion through which a bore is formed parallel to hole 178 and a connecting link 116 secures the two in operable relationship. In other words, the knee lever may be operated at the same time that one or two pedals are depressed by the feet to provide an additional change in the pitch of the instrument.

Additional detail of the adjustable lever arms is shown in FIG. 7 where shaft 174 has a hole 117 formed therein through which lever arm 176 extends therethrough and is secured in place by suitable means such as screws 111. It will be noted that lever arm 176 may have its link increased or decreased. A ledge portion 118 of the frame 13 has a notched portion 119 cut away but the back edge thereof is in close proximity to a barrel 120* which has a plurality of threads 121 formed on the outside thereof,

of which are connected to a pair of flexible cables or 75 the upper portion being connected with lever arm 176 by a pin in hole 178. A nut 122 can be adjusted upwardly or downwardly to control the movement of cable or rod if so desired. Cable or rod 135 has a threaded portion 123 on the end thereof which screws into internal threads formed in the barrel 120' of the mechanism. It will be understood that the other members cooperating with the different shafts are all constructed in the same manner.

Returning again to FIG. 6 and in particular to a structure for anchoring the string at the tuning head end, it will be found that a bore 203 is formed in the end of cam 141 which extends downwardly and towards link 150 in its operable position. Communicating with bore 203, is a cavity 204 which is formed in the end thereof and has a right angled portion which extends through bore 203. A stud 205 is pivotally secured in cavity 204 by the use of a pin 206- and projects into the right angle corner of the cavity so as to intercept the bore 203. The end of stud member 205 has a groove 207 formed in the end thereof to engage the string such as string 15a. In other vwords, string 15a is bottomed at the bottom of bore 203 and stud 205 is pivoted into engagement with the string and by the use of the right angle corner of the cavity, the string is locked in place and secured against movement. The end of stud member 205 has a U-shaped portion 208 formed therein which opens to the end thereof where a cam surface 209 is formed on the face portion. The camming surface 209 is slanted downwardly and towards link 150. Secured in frame 13, is a quick acting type nut of threaded arrangement and in the particular embodiment shown, a quick acting insert 210 is employed. Insert 210 is screwed into the frame in a normal manner and may be of the type supplied by the Reid Tool Supply Company, Muskegon Heights, Mich., carrying a catalog series number QA. As shown, threads are formed in the normal manner on insert 210 at the lower left side and upper right side with a slightly larger bore 211 formed in the insert which will allow a tilta'ble post 212 to be tilted counterclockwise to disengage post 205 at the U-shaped portion 208. Post 212 has a rounded head 213 so that camming surface 209 will provide a smooth engagement therewith. A spring 214 is connected between frame 13 and the lower part of post 212. to provide a bias urging the upper portion of post 212 into engagement with the U-shaped portion 208 of stud 205. A knurled portion 215 of the head of post 212 provides a gripping surface to rotate the screw and thus change the elevation of stud 205 and thus provide a fine tuning for the pitch of the string. It will be observed that in replacing a string, it is only necessary to engage the end of the string in notch 144 and pass the string downwardly into bore 203, lock in place with stud 20 and snap it past the rounded head portion until the flanged head of post 212 engages the U-shaped end of stud 205 and locks it in place.

It will thus be apparent that there has been disclosed a new and improved structure for adjusting the tension on the strings of a musical instrument while playing the instrument so that a key change may take place. The mechanism allows one change to be placed on top of the other so that the musician while having one pedal depressed, may make another change, which may be opposite that originally made. Cooperating with the tuning mechanism, is an improved device for initially setting the tension on the string which provides greater simplicity and each of operation over previous structure.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of the invention which consists of the matter shown and described herein.

What is claimed is:

1. A tuning mechanism for a guitar having a body and a neck with a string under tension anchored thereto passing over the body and neck and tuning head at one end of the guitar neck, said mechanism comprising:

(a) knife edge fulcrum means extending longitudinally away from the tuning head and secured to the guitar body at the end opposite the neck;

(b) first link means having a V-shaped groove formed therein near the upper end thereof cooperating with said knife edge fulcrum means, said first link means having the string anchored thereto and passing over the upper edge of said link means;

(c) second link means pivotally secured to the lower end of said first link means;

(d) first arm means pivotally connected to said second link means in spaced relationship from said first link means;

(e) second arm means pivotally connected to said second link means at the lower end thereof;

(f) spring means connected to said second link means below said second arm means and said guitar body to apply a constant spring bias along said second arm means in opposition to the movement thereof;

(g) first stop means engaging said first and second arm means and restraining said arm means against movement towards said link means;

(h) and first selectable actuating means for selectably moving one of said first and second arm means away from said link means to change the tension in the guitar string.

2. The invention as set forth in claim 1 including:

(i) adjustable length controlling means connecting said first stop means to said arm means to tune said string to a predetermined pitch when said link means is at rest.

3. The invention as set forth in claim 1 including:

(j) second stop means engaging said first and second arm means to limit the increase or decrease in the tension on said string by a predetermined amount.

4. The invention as set forth in claim 1 including:

(k) second stop means cooperating with said first selectable actuating means to limit the increase or decrease in the tension on said string by a predetermined amount.

5. The invention as set forth in claim 1 wherein said first arm means and said second means include:

(1) a V-shaped notch formed in said second link means on the side opposite said knife edge fulcrum means and a looped portion formed on the end of said arm means and cooperatively engaging said V-shaped notch to provide a pivotal connection.

6. The invention as set forth in claim 1 wherein said first selectable actuating means includes:

(m) lever means pivotally connected to said guitar body, said lever means being pivotally secured to one of said first or second arm means;

(n) and a foot operated control rod extending substantially vertically from said lever means to impart rotation thereof which causes said first and second arm means to move away from said second link means.

7. The invention as set forth in claim 6 wherein said lever means includes:

(0) a first lever arms pivotally connected to one of said arm means;

(p) and a second adjustable lever arm secured to said first lever arm for changing the amount of force required to cause a movement of said first or second arm means.

8. The invention as set forth in claim 1 including:

(q) a cam means over which said string passes, said cam means being rotatably secured to said neck and having a cavity formed therein;

(r) a stud member pivotally secured in said cavity of said cam means and having said string engaged therewith to secure and set the tension on said string; 7

( s) and a locking member secured to said neck and cooperating with said cam means to rotatably move and hold said cam means at a selectable position.

9. The invention as set forth in claim 1 including:

(t) second selectable actuating means for selectively moving at least one of said first and second arm mean-s away from said link means to increase or decrease the tension in the guitar string.

10. The invention as set forth in claim 9 including:

(11) lost motion means connected to at least one of said first and second arm means and said cooperating first and second selectable actuating means causing movement the first instance one of said selectable actuating means are actuated to move the same arm means.

11. The invention as set forth in claim 1 including:

(v) second spring means connected to said second link means between said first arm means and the pivotal connection with said first link means and said guitar .body to apply a constant spring bias along said first arm means to aid in the movement thereof.

12. The invention as set forth in claim 3 including:

(w) guide means secured to each end of said guitar body cooperating with said first and second arm means and said first and second stop means to set the tension of the cooperating guitar string when at rest and to limit the change in tension on said string by a predetermined amount.

13. The invention as set forth in claim 1 including:

(a) a cam means over which said string passes, said cam means being rotatably secured to said neck and having a bore formed threin below the axis of rotation;

(b) a thumb screw secured to said neck and cooperating with said cam means to rotatably move and hold said cam means at a selectable position;

(c) a stud member rotatably secured in said bore of said cam means and having said string wound thereabout to set the tension on said string;

(d) and a stud locking member locking said stud against rotation in said 'bore.

14. The invention as set forth in claim 1 including:

(e) a cam means over which said string passes, said cam means being rotatably secured to said neck and having a recessed portion for receiving said srting;

(f) a stud member secured to said cam means and arranged to rotate said cam means therewith, the end thereof having a camming surface slanting downwardly and rearwardly when at, or near, an operable position;

(g) and a tiltable post pivotally secured to said neck and extending upwardly to engage caid camming surface of said stud member, said tiltable post having a flange portion engaging the upper surface of said stud member when said stud member is in operable position.

15. The invention as set forth in claim 14 including:

(i) releasable fastening means cooperatively engaging said tiltable post and said neck providing means for lengthening and shortening the amount said tiltable post extends above said neck.

16. The invention as set forth in claim 14 including:

(j) a bore formed in said cam means through an end portion generally facing away from said link means;

(k) a cavity communicating with said bore and extending through said bore along a portion thereof, said cavity and bore being constructed and arranged to receive said string therein;

(1) and pin means pivotally securing said stud member to said cam means and to engage said string in said cavity and bore and secure said string against slip ing.

17. The invention as set forth in claim 1 wherein said first and second arm means includes cable means under tension.

18. The invention as set forth in claim 1 including:

:(h) a cam means over which said string passes, said cam means being rotatably secured to said neck and having a recessed portion :for receiving said string;

(i) a stud member secured to said cam means and arranged to rotate said cam means therewith, the end thereof having a yoke portion extending outwardly and away from said cam means;

(j) and a locking member releasably secured to said neck and extending upwardly to engage said yoke portion of said stud member, said locking member having a flange portion cooperatively engaging the upper surface of said yoke portion when said stud member is in operable position.

19. The invention as set forth in claim 18 including:

(k) resilient biasing means secured between said movable locking member and said guitar body biasing said locking member into engagement with said yoke portion.

20. The invention as set forth in claim 1 including:

(1) a cam means over which said string passes, said cam means being rotatably secured to said neck and having a recessed portion for receiving said string;

(In) a stud member secured to said cam means and arranged to rotate said cam means therewith, the end thereof having a first locking member secured thereto and adapted to engage another locking member;

(11) and a second locking member secured to said neck and extending into operable engagement with said first locking member of said stud member, said first and second locking members securing said stud member and cam means against movement when in operable position.

21. A tuning mechanism for a guitar having a body and a neck with a plurality of strings under tension anchored thereto passing over the body and neck with a tuning head at the far end of the guitar neck, said mecha- IllSm compnsmg:

(a) a plurality of knife edge fulcrums, there being as many as there are strings, said fulcrums extending longitudinally away from the tuning head and securid to the guitar body at the end opposite the nec (b) a plurality of first links, each having a V-shaped groove formed therein near the upper end thereof cooperatively engaging one of said knife edge fulcrums and having a string anchored thereto and passing over the upper edge of said link;

(c) a plurality of second links, each pivotally secured to the lower end of a cooperating link of said plurality of first links;

((1) a plurality of first arms, each pivotally connected to a cooperating link of said plurality of second links irrlcllc disposed in spaced relationship from said first m (e) a plurality of second arms, each pivotally connected to a cooperating link of said plurality of second links as the lower end thereof;

(f) a plurality of spring means connected below said plurality of second links at substantially the end thereof and said guitar body to apply constant bias to said links in opposition to the movement thereof;

(g) a plurality of first stops engaging said plurality of first and second arms and restraining said arms against movement toward said plurality of links;

(h) a plurality of shafts rotatably secured to said guitar body in a direction transverse to the neck thereon and disposed along said guitar body and neck;

(i) a plurality of foot pedals, each having connecting means cooperating with said plurality of shafts to produce rotation thereof;

(j) and a plurality of levers secured to said plurality of shafts, there being at least one half as many levers .on each shaft as there are strings, certain of said levers selectably engaging one of said first or second arms cooperating therewith to increase or decrease the tension in the cooperating string of said plurality of strings.

22. The invention as set forth in claim 21 including:

(k) a plurality of lost motion devices connected between said plurality of levers and said plurality of first and second arms, said devices selectively con- References Cited necting certain of said levers to certain of said first UNITED STATES PATENTS and second arms.

. 3,352,188 11/1967 Fender 84-312 23. The invention as set forth in claim 22 wherein:

(1) said lost motion devices and said first and second 5 arms are disposed radially in the same direction RICHARD WILKINSON Exammer' along each of said plurality of levers so that the GONZALES, Assistant Examiner, same directional rotation of said shafts will produce 7 both an increase and decrease in the tension in said strings. 10 "7 

